I could see changing it, but in the case of the Trader Joe's discussions, I think it's somewhat less important. Here's why:

In these threads, I think the word OLD is actually doing two things. First, it lets regular contributors know that the discussion at hand is not the most recent one. This seemed to really be the sole purpose of putting OLD on the What's For Dinner threads, and now we put (Thru _____) instead.

However, I would argue that unlike the What's For Dinner threads, the information you find in the Trader Joe's thread is actually somewhat time-sensitive. In other words, if I was looking for info about the best Trader Joe's products, I might not want to be in a discussion from last year, since it's possible that Trader Joe's no longer even carries some of the items. So the second thing the word OLD is doing is acting as a deterrent, which in this case might not be as big a problem. On the other hand, if I'm looking for inspiration on what to cook for dinner, it doesn't necessarily matter if that discussion is recent or old, which is why having the deterrent isn't a good idea.

Having said all of that, the Trader Joe's discussions already have dates on them, so I don't really think the OLD is necessary, either.

I no longer babysit the TJ and Costco threads but when I WAS the one updating them quarterly, I added the "OLD" to the title whenever re-upping with a new thread, because MANY people were continuing to add to the old thread, even when a link to the new one was included in the replies to the old one.